1 files changed, 180 insertions, 17 deletions

diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index 41b223a59a63..f0cf2714ec52 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -1,10 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef LINUX_EXPORTFS_H
 #define LINUX_EXPORTFS_H 1
 
 #include <linux/types.h>
+#include <linux/path.h>
 
 struct dentry;
+struct iattr;
 struct inode;
+struct iomap;
 struct super_block;
 struct vfsmount;
 
@@ -96,6 +100,40 @@ enum fid_type {
 	FILEID_FAT_WITH_PARENT = 0x72,
 
 	/*
+	 * 64 bit inode number, 32 bit generation number.
+	 */
+	FILEID_INO64_GEN = 0x81,
+
+	/*
+	 * 64 bit inode number, 32 bit generation number,
+	 * 64 bit parent inode number, 32 bit parent generation.
+	 */
+	FILEID_INO64_GEN_PARENT = 0x82,
+
+	/*
+	 * 128 bit child FID (struct lu_fid)
+	 * 128 bit parent FID (struct lu_fid)
+	 */
+	FILEID_LUSTRE = 0x97,
+
+	/*
+	 * 64 bit inode number, 32 bit subvolume, 32 bit generation number:
+	 */
+	FILEID_BCACHEFS_WITHOUT_PARENT = 0xb1,
+	FILEID_BCACHEFS_WITH_PARENT = 0xb2,
+
+	/*
+	 *
+	 * 64 bit namespace identifier, 32 bit namespace type, 32 bit inode number.
+	 */
+	FILEID_NSFS = 0xf1,
+
+	/*
+	 * 64 bit unique kernfs id
+	 */
+	FILEID_KERNFS = 0xfe,
+
+	/*
 	 * Filesystems must not use 0xff file ID.
 	 */
 	FILEID_INVALID = 0xff,
@@ -109,7 +147,11 @@ struct fid {
 			u32 parent_ino;
 			u32 parent_gen;
 		} i32;
- 		struct {
+		struct {
+			u64 ino;
+			u32 gen;
+		} __packed i64;
+		struct {
  			u32 block;
  			u16 partref;
  			u16 parent_partref;
@@ -117,10 +159,38 @@ struct fid {
  			u32 parent_block;
  			u32 parent_generation;
  		} udf;
-		__u32 raw[0];
+		DECLARE_FLEX_ARRAY(__u32, raw);
 	};
 };
 
+enum handle_to_path_flags {
+	HANDLE_CHECK_PERMS   = (1 << 0),
+	HANDLE_CHECK_SUBTREE = (1 << 1),
+};
+
+struct handle_to_path_ctx {
+	struct path root;
+	enum handle_to_path_flags flags;
+	unsigned int fh_flags;
+};
+
+#define EXPORT_FH_CONNECTABLE	0x1 /* Encode file handle with parent */
+#define EXPORT_FH_FID		0x2 /* File handle may be non-decodeable */
+#define EXPORT_FH_DIR_ONLY	0x4 /* Only decode file handle for a directory */
+
+/*
+ * Filesystems use only lower 8 bits of file_handle type for fid_type.
+ * name_to_handle_at() uses upper 16 bits of type as user flags to be
+ * interpreted by open_by_handle_at().
+ */
+#define FILEID_USER_FLAGS_MASK	0xffff0000
+#define FILEID_USER_FLAGS(type) ((type) & FILEID_USER_FLAGS_MASK)
+
+/* Flags supported in encoded handle_type that is exported to user */
+#define FILEID_IS_CONNECTABLE	0x10000
+#define FILEID_IS_DIR		0x20000
+#define FILEID_VALID_USER_FLAGS	(FILEID_IS_CONNECTABLE | FILEID_IS_DIR)
+
 /**
  * struct export_operations - for nfsd to communicate with file systems
  * @encode_fh:      encode a file handle fragment from a dentry
@@ -130,13 +200,13 @@ struct fid {
  * @get_parent:     find the parent of a given directory
  * @commit_metadata: commit metadata changes to stable storage
  *
- * See Documentation/filesystems/nfs/Exporting for details on how to use
+ * See Documentation/filesystems/nfs/exporting.rst for details on how to use
  * this interface correctly.
  *
  * encode_fh:
  *    @encode_fh should store in the file handle fragment @fh (using at most
  *    @max_len bytes) information that can be used by @decode_fh to recover the
- *    file referred to by the &struct dentry @de.  If the @connectable flag is
+ *    file referred to by the &struct dentry @de.  If @flag has CONNECTABLE bit
  *    set, the encode_fh() should store sufficient information so that a good
  *    attempt can be made to find not only the file but also it's place in the
  *    filesystem.   This typically means storing a reference to de->d_parent in
@@ -149,12 +219,13 @@ struct fid {
  *    @fh_to_dentry is given a &struct super_block (@sb) and a file handle
  *    fragment (@fh, @fh_len). It should return a &struct dentry which refers
  *    to the same file that the file handle fragment refers to.  If it cannot,
- *    it should return a %NULL pointer if the file was found but no acceptable
- *    &dentries were available, or an %ERR_PTR error code indicating why it
- *    couldn't be found (e.g. %ENOENT or %ENOMEM).  Any suitable dentry can be
- *    returned including, if necessary, a new dentry created with d_alloc_root.
- *    The caller can then find any other extant dentries by following the
- *    d_alias links.
+ *    it should return a %NULL pointer if the file cannot be found, or an
+ *    %ERR_PTR error code of %ENOMEM if a memory allocation failure occurred.
+ *    Any other error code is treated like %NULL, and will cause an %ESTALE error
+ *    for callers of exportfs_decode_fh().
+ *    Any suitable dentry can be returned including, if necessary, a new dentry
+ *    created with d_alloc_root.  The caller can then find any other extant
+ *    dentries by following the d_alias links.
  *
  * fh_to_parent:
  *    Same as @fh_to_dentry, except that it returns a pointer to the parent
@@ -163,20 +234,26 @@ struct fid {
  * get_name:
  *    @get_name should find a name for the given @child in the given @parent
  *    directory.  The name should be stored in the @name (with the
- *    understanding that it is already pointing to a a %NAME_MAX+1 sized
+ *    understanding that it is already pointing to a %NAME_MAX+1 sized
  *    buffer.   get_name() should return %0 on success, a negative error code
- *    or error.  @get_name will be called without @parent->i_mutex held.
+ *    or error.  @get_name will be called without @parent->i_rwsem held.
  *
  * get_parent:
  *    @get_parent should find the parent directory for the given @child which
  *    is also a directory.  In the event that it cannot be found, or storage
  *    space cannot be allocated, a %ERR_PTR should be returned.
  *
+ * permission:
+ *    Allow filesystems to specify a custom permission function.
+ *
+ * open:
+ *    Allow filesystems to specify a custom open function.
+ *
  * commit_metadata:
  *    @commit_metadata should commit metadata changes to stable storage.
  *
  * Locking rules:
- *    get_parent is called with child->d_inode->i_mutex down
+ *    get_parent is called with child->d_inode->i_rwsem down
  *    get_name is not (which is possibly inconsistent)
  */
 
@@ -191,12 +268,96 @@ struct export_operations {
 			struct dentry *child);
 	struct dentry * (*get_parent)(struct dentry *child);
 	int (*commit_metadata)(struct inode *inode);
+
+	int (*get_uuid)(struct super_block *sb, u8 *buf, u32 *len, u64 *offset);
+	int (*map_blocks)(struct inode *inode, loff_t offset,
+			  u64 len, struct iomap *iomap,
+			  bool write, u32 *device_generation);
+	int (*commit_blocks)(struct inode *inode, struct iomap *iomaps,
+			     int nr_iomaps, struct iattr *iattr);
+	int (*permission)(struct handle_to_path_ctx *ctx, unsigned int oflags);
+	struct file * (*open)(const struct path *path, unsigned int oflags);
+#define	EXPORT_OP_NOWCC			(0x1) /* don't collect v3 wcc data */
+#define	EXPORT_OP_NOSUBTREECHK		(0x2) /* no subtree checking */
+#define	EXPORT_OP_CLOSE_BEFORE_UNLINK	(0x4) /* close files before unlink */
+#define EXPORT_OP_REMOTE_FS		(0x8) /* Filesystem is remote */
+#define EXPORT_OP_NOATOMIC_ATTR		(0x10) /* Filesystem cannot supply
+						  atomic attribute updates
+						*/
+#define EXPORT_OP_FLUSH_ON_CLOSE	(0x20) /* fs flushes file data on close */
+#define EXPORT_OP_NOLOCKS		(0x40) /* no file locking support */
+	unsigned long	flags;
 };
 
+/**
+ * exportfs_cannot_lock() - check if export implements file locking
+ * @export_ops:	the nfs export operations to check
+ *
+ * Returns true if the export does not support file locking.
+ */
+static inline bool
+exportfs_cannot_lock(const struct export_operations *export_ops)
+{
+	return export_ops->flags & EXPORT_OP_NOLOCKS;
+}
+
 extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,
-				    int *max_len, struct inode *parent);
+				    int *max_len, struct inode *parent,
+				    int flags);
 extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
-	int *max_len, int connectable);
+			      int *max_len, int flags);
+
+static inline bool exportfs_can_encode_fid(const struct export_operations *nop)
+{
+	return !nop || nop->encode_fh;
+}
+
+static inline bool exportfs_can_decode_fh(const struct export_operations *nop)
+{
+	return nop && nop->fh_to_dentry;
+}
+
+static inline bool exportfs_can_encode_fh(const struct export_operations *nop,
+					  int fh_flags)
+{
+	/*
+	 * If a non-decodeable file handle was requested, we only need to make
+	 * sure that filesystem did not opt-out of encoding fid.
+	 */
+	if (fh_flags & EXPORT_FH_FID)
+		return exportfs_can_encode_fid(nop);
+
+	/* Normal file handles cannot be created without export ops */
+	if (!nop)
+		return false;
+
+	/*
+	 * If a connectable file handle was requested, we need to make sure that
+	 * filesystem can also decode connected file handles.
+	 */
+	if ((fh_flags & EXPORT_FH_CONNECTABLE) && !nop->fh_to_parent)
+		return false;
+
+	/*
+	 * If a decodeable file handle was requested, we need to make sure that
+	 * filesystem can also decode file handles.
+	 */
+	return exportfs_can_decode_fh(nop);
+}
+
+static inline int exportfs_encode_fid(struct inode *inode, struct fid *fid,
+				      int *max_len)
+{
+	return exportfs_encode_inode_fh(inode, fid, max_len, NULL,
+					EXPORT_FH_FID);
+}
+
+extern struct dentry *exportfs_decode_fh_raw(struct vfsmount *mnt,
+					     struct fid *fid, int fh_len,
+					     int fileid_type,
+					     unsigned int flags,
+					     int (*acceptable)(void *, struct dentry *),
+					     void *context);
 extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
 	int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *),
 	void *context);
@@ -204,10 +365,12 @@ extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
 /*
  * Generic helpers for filesystems.
  */
-extern struct dentry *generic_fh_to_dentry(struct super_block *sb,
+int generic_encode_ino32_fh(struct inode *inode, __u32 *fh, int *max_len,
+			    struct inode *parent);
+struct dentry *generic_fh_to_dentry(struct super_block *sb,
 	struct fid *fid, int fh_len, int fh_type,
 	struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
-extern struct dentry *generic_fh_to_parent(struct super_block *sb,
+struct dentry *generic_fh_to_parent(struct super_block *sb,
 	struct fid *fid, int fh_len, int fh_type,
 	struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));